The production of water fit for human consumption from water contaminated by micro-organisms, chemicals, heavy metals and minerals is a requirement throughout the world. Many different proposals have been made for the purification of contaminated water.
The most popular system in widespread use for the purification of contaminated water is a pitcher wherein contaminated water is passed through a filter made of a combination of a porous media filter, activated carbon, and an ion exchange resin and into a clean water reservoir within the pitcher. This type of system will reduce the levels of chlorine, lead, and pesticides. However, there are several disadvantages associated with this device. The first disadvantage of this water purification system is that the structure of the filter provides a breeding ground for microorganisms thereby multiplying the dangers of microorganisms which may be present in very low numbers. Another disadvantage of such a water purification system is that the filter life is not measured and it is possible for the user to employ the filter beyond its useful life. A further disadvantage of such a water purification system is that oils and fuels often present in water drawn from lakes and rivers are not readily removed and that said oils and fuels tend to coat the filters and damage their operational life and effectiveness. Some filtration based products now incorporate a means of measuring the water volume passing though the filter and an indicator as to when to change the filter. Other filters incorporate an iodine product to minimize the risk of microbiological hazards, however, these materials often impart undesirable tastes and many are potential carcinogens.
Another popular system in use for the purification of contaminated water is a system which employs an ultraviolet light for disinfection in series with a porous media and carbon filter. This type of system will reduce the levels of chlorine, lead, and pesticides and has some disinfection capability. However, there are several disadvantages associated with this device. The first disadvantage of this water purification system is that the ultraviolet light's disinfection efficacy is greatly diminished by turbidity or color in the water which can cause the filter to become contaminated by microorganisms which can readily live and breed therein thereby multiplying the danger from any microorganisms which may be present. Another disadvantage of such a water purification system is that the filter life is not measured and it is possible for the user to employ the filter beyond its useful life. A further disadvantage of such a water purification system is that oils and fuels often present in water drawn from lakes and rivers are not readily removed and that said oils and fuels tend to coat the filters and damage their operational life and effectiveness. Some filtration based products now incorporate a means of measuring the water volume passing though the filter and an indicator as to when to change the filter. Other filters incorporate an iodine product to minimize the risk of microbiological hazards, however, these materials often impart undesirable tastes and many are potential carcinogens.
Clearly therefore, it is desirable that the design of a water purification system will employ a filtration stage prior to ozone, ozone for disinfection and oxidation, and a post ozone filtration stage to remove any residual ozone and products of ozonation from the water before consumption. It is also desirable that the design of a water purification system will employ a means of ensuring, disinfection efficacy. It is also desirable that the design of a water purification system will employ a means of monitoring the filter usage and provide the user with an indication to change the filter.